Add Overworld accessors and enhance testing framework

- Introduced new methods in `Controller`, `EditorManager`, and `OverworldEditor` to access the `Overworld` instance, improving modularity and interaction with the overworld data.
- Added `GetTile` method in `Overworld` to retrieve tile data based on coordinates, enhancing functionality for tile manipulation.
- Implemented a new testing framework with automated GUI tests, including `CanvasSelectionTest` and `FrameworkSmokeTest`, to validate user interactions and ensure robustness.
- Updated `CMakeLists.txt` to include new test files and dependencies, streamlining the build process for testing.
- Refactored logging behavior to ensure proper file handling during logging operations, improving reliability in logging outputs.

src/util/log.h

@@ -42,7 +42,7 @@ static void logf(const absl::FormatSpec<Args...> &format, const Args &...args) {
   // Reopen file if path changed
   if (g_log_file_path != last_log_path) {
     fout.close();
-    fout.open(g_log_file_path, std::ios::out | std::ios::app);
+    fout.open(g_log_file_path, std::ios::out | std::ios::trunc);
     last_log_path = g_log_file_path;
   }